Dimmers for incandescent light bulbs are in wide use in the lighting industry, and are installed in millions of buildings worldwide. Dimmers are used to cause bulbs to provide less light than they would if provided with the full power from the main circuit. In most electrical systems, main power is provided with alternating current (AC). Dimmers operate by “chopping up” the AC signal—specifically, for a given cycle of the AC wave, preventing some proportion of the wave from being transmitted to the luminaire. As more dimming is desired, a larger proportion of the wave is blocked. By blocking a portion of the wave, the total root-mean-square (“RMS”) voltage provided to the light source falls.
This system of dimming is very effective for incandescent bulbs, for which the total illumination has a direct relationship with the RMS voltage provided to the bulb. This dimming technology does not work as well, however, for some other types of light sources, including, but not limited to, luminaires with light emitting diode (“LED”) light sources, organic light emitting diode (“OLED”) light sources, or compact fluorescent bulbs. This is because OLED light sources, LED light sources, and compact fluorescent bulbs have an electronic ballast (for compact fluorescent bulbs) or driver (for OLED and LED light sources) that converts the main current into current that is appropriate for the given light source. The ballast/driver requires electrical power to perform its conversion. When the power provided to the ballast/driver is reduced by the dimmer, the ballast/driver may not function properly. This may manifest itself in several ways. For example, the light source may fail to illuminate entirely, or there may be a noticeable delay before the light source illuminates. In lighting applications, neither result is desirable.